In Vitro and In Vivo Antibacterial Activities of Patchouli Alcohol, a Naturally Occurring Tricyclic Sesquiterpene, against Helicobacter pylori Infection

This study further evaluated the and anti- activities and potential underlying mechanism of patchouli alcohol (PA), a tricyclic sesquiterpene. In the assay, the capacities of PA to inhibit and kill were tested on three standard strains at different pH values and on 12 clinical isolates. The effects of PA on adhesion (and its , , and genes), motility (and its and genes), ultrastructure, and flagellation were investigated. Moreover, the resistance to and postantibiotic effect (PAE) of PA were determined. Furthermore, the effects of PA on eradication and gastritis were examined. Results showed that MICs of PA against three standard strains (pH 5.3 to 9) and 12 clinical isolates were 25 to 75 and 12.5 to 50 μg/ml, respectively. The killing kinetics of PA were time and concentration dependent, and its minimal bactericidal concentrations (MBCs) were 25 to 75 μg/ml. In addition, adhesion, motility, ultrastructure, and flagellation were significantly suppressed. PA also remarkably inhibited the expression of adhesion genes ( and ) and motility genes ( and ). Furthermore, PA treatment caused a longer PAE and less bacterial resistance than clarithromycin and metronidazole. The study showed that PA can effectively eradicate , inhibit gastritis, and suppress the expression of inflammatory mediators (COX-2, interleukin 1β, tumor necrosis factor alpha, and inducible nitric oxide synthase [iNOS]). In conclusion, PA can efficiently kill , interfere with its infection process, and attenuate gastritis with less bacterial resistance, making it a potential candidate for new drug development.